Will not be able to give a definite account of parentage. Maybe once it has bloomed it would be easier to give an idea, but not precise identification as there are so many crosses it would make it difficult.

This tree, although looking tall. Seems like it has elongated growth between the internodes (distance between the "D" marks from where leaves once where). This could mean that it is the trees genetic growth rate or it may need more sunlight. Generally when trees are given alot of sunlight, they grow lower and more compact.

I would probably prune this tree half way between the soil level and the "Y" of main stem.

Rick